This invention relates to a process for making olefinic organic compounds by removing two vicinal chlorine atoms from the corresponding dichloro or polychloro compounds.
Olefinic organic compounds are characterized by the presence of a carbon-carbon double bond &gt;C.dbd.C&lt;. They are normally made by dechlorination of vicinal dichloro compounds with metallic zinc or magnesium. While this technique gives satisfactory results in most cases, it sometimes is unreliable or gives low yields, especially where the starting dichloro compound also carries a fluorine atom on one of the vicinal chlorine-carrying carbon atoms. A case in point is the dechlorination of 4,5-dichloro-4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxolane (1) to 4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole (2), as shown in the following equation (A): ##STR1##
This reaction, described in U.S. Pat. No. 3,865,845 to Resnick, is erratic; the desired product is in some runs obtained in satisfactory yields, while in other runs it is obtained either in low yields or not at all.
It thus is desirable to provide a reliable and reproducible process for effecting such dechlorinations in good yields.